Electrical control system



Patented Nov. 12,1840

UNITED STATESv amcmcar. CONTROL SYSTEM 'Danilo Santini, Tenafly, N. J., assignor to Westinghouse Electric Elevator Company, Jersey City, N. 1., a corporation of Illinois Application Aprild, 1940, Serial No. 327,819

11 Claims.

My invention relates to electrical control systerns of the variable voltage or Ward-Leonard type and more particularly to control systems of this character which embody regulating apparatus and which are especially adapted for the operation of elevator hoisting motors..

One object of my invention is to provide a variable voltage control system which may be constructed, installed, operated, and maintained in operation at a lower cost than the cost of the variable voltage control systems heretofore provided and to thereby provide for the economical use of variable voltage control systems for smaller installations than has heretofore been practical from a cost standpoint. v

Another object is to provide a variable voltage control system in which the generator field may be readily controlled to obtain the most desirable regulation and excitation.

A further object is to provide a variable con- I For a better understanding oi. the invention,

reference may be had to the accompanying drawings, in which:

Figure 1 is a diagrammatic representation of an elevator installation embodying my invention;

Fig. 2 is -a diagrammatic representation, in

what is known as the straight line style, of the control system for operating the elevator car shown in Fig. l;

Fig. 2A is an explanatory illustration of the relays embodied in the control system of Fig. 2. The illustration of the relays in Fig. 2A shows them with their coils and contact members disposed in horizontal alignment with their positions in the straight line circuits of Fig. 2 so 5 that the identification of any relay and the position of its coil and its contact members in the straight line circuits may be readily determined; and

Fig. 3 is a diagrammatic representation of the 50 regulator illustrated in Fig. 1 and the application of its four field windings to its field yoke.

Referring more particularly to Fig. 1 of the drawings, I have illustrated a car C as suspended by a suitable cable H which passes over a hoisting drum 1: tea suitable counterweight H. A

hoisting motor H is provided for operating the hoisting drum bymeans of a shaft l4 and a worm gear drive l5 to raise and lower the car. A generator G is provided for supplying electrical energy to the hoisting motor.

A regulating generator (hereinafter called the regulator) is provided for exciting the generator and regulating. its output, and an exciter EX is provided for supplying electrical energy to a control circuit for the elevator and for exciting the 10 hoisting motor. A driving motor M, which may be provided'wlth electrical power from any suitable source such as is represented by the conductors I, II and III, is provided for driving the generator, the regulator and the exciter at constant 15 speed by means of a shaft l6. v

An electromagnetic brake B is associated with the shaft [4 for stopping and holding the car when the power to the hoisting motor is cut off.

A car switch CS is mounted in the car for use 20 by the car attendant in causing the car to start and stop. The car may be started in the up direction by moving the. car switch counter-clockwise and in the down direction by moving it clockwise. When the car switch is centered, it 25 causes the car to stop at the next floor.

I do not care to be limited in the application of my invention to control systems operated by a car switch as it will be evident to those skilled in the art that my invention may be applied to 30 any form of automatic control such as the various push-button control systems.

Fig. 2 illustrates the control system for the car as provided with a pair of supply conductors L+1 and L-l, which are connected, for ener- 5 gization, to the armature EXA of the exciter EX. The field winding EXF oi the exciter is connected across the terminals of its armature. The hoisting motor H is provided with an armature HA and a field winding HF, the field. winding being 40 connected across the supply conductors L+1 and L-1 for constant energization.

A variable voltage system of control is provided for controlling the operation of the hoisting motor H wherein the hoisting motor armature HA is connected in a closed circuit H with the armature GA of the generator G. The generator is provided with a separately excited field inding GF which is connected for energization in a loop circuit l8 with the armature RA oi. the regulator R, so that the output of the generator, and consequently the speed and direction of operation of the hoisting motor H, may be controlled by controlling the operation of the regulator. An adjustableresistor T2 is connected in the circuit oi the generator field winding for adlusting the resistance of that circuit to any desired value.

The regulator is provided with a self-exciting s field winding RCF, a pattern field winding RPF, a differential field winding RDF, and a series field winding RSF, as shown in Figs. 2 and 3.

The self-exciting field winding RCF is connected in the loop circuit l8 (Fig. 2) in series with the regulator armature RA and the generator field winding GB. The total resistance oi this circuit should be made equal to the volts that the regulator will produce when one ampere fiows through its self-exciting field winding. In other words, the circuit is tuned so that perfect regulation will be obtained with no hunting e1- iects.

The pattern field winding RP!" is disposed to be connected across the supply conductors L+l and L-l so that the generator voltage and the direction or operation may be controlled by controlling the direction and the value or the current in the pattern field. For a given excitation oi the pattern field, the regulator will produce a voltage which will excite the generator field winding GF. As soon as current starts to flow through the generator fieldwinding circuit, the self-exciting field winding RCF excites the regulator to force the current through the generator field winding.

. A resistor r! is connected in the circuit of the pattern field winding to control the value of that winding, and a high speed relay V is provided for short circuiting this resistor when the car is to be operated at its normal high speed. T

An up direction switch U and a down direction switch D are provided for connecting the pattern field to the supply conductors L+l and Ll for causingthe car to be operated in the up direc- 40 tion or in the down direction. The direction relays and the high speed relay are controlled by the car switch CS. I

The difierential field winding RDF is connected across the terminals of the generator armature as GA. An adjustable resistor H is inserted in series with'the diilerential field winding RDF, so that the value of the differential field winding may be adjusted as desired. This differential field winding and the pattern field winding RP! are adjusted to produce the same and opposite voltage in the regulator for a given excitation of the-pattern field. Under these conditions, the generator voltage will always build up to the value indicated by the pattern field. If, for any. be reason, a, drop in voltage takes place in the generator, that causes the strength or theregulator differential field to be less than that of the pattern field, thus creating a voltage difierential in the regulator which, by the action of its selfao exciting field, will quickly and smoothly bring the generator voltage to the value indicated by the pattern field. In other words, the desired and the actual voltage in the generator will revmain the same by reason of the eflect of the ebpattern field and the diflerential field, regardless of any load condition in the generator tending to 7 6 the excitation of the regulator different l fi ld also increases. the strength or this field being such that when the. generator reaches the voltage predetermined by the pattern field, the regulator stops building up, maintaining the required generator shunt field excitation to produce the voltage.

The regulator series field R8! is connected in series in the loop circuit l1 between the armatures of the generator and the hoisting motor. This field winding is provided to cause the regulator to give the generator field winding suiiicient excitation to compensate for the RI drop in the hoisting motor. As the current increases in the armature oi the generator, the voltage will rise just enough to overcome the RI drop of this current fiowing through the hoisting motor armature. The net result will be a fiat speed for the hoisting motor regardless of load and regardless of the selected value oi. that speed. Anything which tends to disturb this relati n will be automatically compensated for by e reaction oi the field windings previously described.

The electromagnetic brake B is provided with a magnetizing coil I! which is energized to release the brake when the up or the down direction switch is operated to cause movement of the car in its hatchway. Inasmuch as there is likely to be some lag in the starting of the hoisting motor after a direction switch is operated to start the car'by reason of the time it takes the regulator and the generator to build up. the contact members UI and DI of the direction switches are provided with dashpots Ill and II to delay the operation of the brake coil to release the brake for a predetermined time after the pattern field oi the regulator is energized to start the car. The

length of the predetermined delay maybe ad- 1 Justed to insure the holding of the car by the brake until the hoisting motor becomes elective.

It is believed that the invention will be better understood by the following assumed operation. It will be assumed that the car is standing at its lower terminal and that power applied through the supply conductors I, II and III (Fig. l) to the driving motor M, thus causing that motor to start rotating the shaft II, and thus operating the armature m of the exciter, the armatune GA oi the generator and the armature RA 0! the regulator. The operation of the exciter armature EXA causes the exciter to supply energy to the supply conductors L+1 and L-l, thereby energizing the field winding H! of the hoisting mo- The rotation of the regulator armature RA does not afi'ect the loop circuit 1. or the generator field winding GI" because. as before stated, the

self-exciting field winding RC1" oi the regulator is so designed that it generates just sumcient voltage to send the current through the loop circuit in which the generator field winding is disposed. Hence, the generator field winding is not energized and the generator does not now supply any current to the hoisting motor.

As a suitable landing system for causing the car to stop level with the fioor when the car switch is centered for a stop, I have illustrated an automatic inductor relay landing system similar to that disclosed in Patent No. 1,884,446, is-

sued October 25, 1932, to K. H. White and G.H. Hearn and assigned to the Westinghouse Electric '8: Manufacturing Company. The landing system includes a high speed decelerating inductor relay E and a stopping inductor relay 1'' for causing the car to be automatically decele ated i om its h g sp d. and stopped e ac Cal ' 6 plates mounted on the hatchway wall.

The up direction plate UE is for operating the relay'E to open its contact members El. The up direction plate UF is for operating the relay F to open its contact members PI. The down 10 direction plate DE is for operating the relay E to open its contact members E2. The plate DF is for operating the relay F to open its contact members F2. The plates will not operate the relays unless they are energized and the relays are energized only when the car switch is cen-' tered to cause the car to stop at a floor.

The contact members of the decelerating inductor relay E are disposed in the circuit of the high speed relay V. The contact members of the supporting relay F are disposed in the circuits oi! the direction relays U and D. When the car switch is centered, for a stop, it energizes the inductor relays. When relay E is energized and comes opposite its inductor plate, it opens 2 its contact members in the circuit of the high speed relay and thus decelerates the car to landing speed. When relay F is energized and comes opposite its inductor plate, it opens its contact members and thus, stops the car at the fioor. It will be assumed now that the attendant in the car moves the car switch CS in counterclockwise direction to cause the car to move upwardly.

Briefly, the movement of the car switch for up direction energizes the up direction relay U which releases the brake B and energizes the pattern field RPE' The energized pattern field RPF causes the regulator R to energize the field GF or the generator, which causes the generator G to generate current to energize the hoisting motor H and thereby move the car upwardly.

This operation, in detail, is as follows: The movement of the car switch closes the contact members CSI and 22 to energize the up direction switch U to effect an upward movement of the car. This circuit extends n+1, cs, CSI, :2, FLU, u, s, L-l.

The energized up direction relay U closes its selfholding contact members U5, closes its contact members U2, U3 and U4, and starts its contact members Ul in closing operation. A The closing of the contact members U2 an U3 energizes the pattern field RPF by the circuit 55 extending L+1, U2, RPF, U3, r3, L-1 1 As soon as current starts to flow through the pattern field circuit, the regulator field RCF self a excites the regulator to force current through the generator field. As the current in the generator field increases, the excitation oi. the regulator difierential field RDF also increases, the rength of this field being such that, when the generator reaches the voltage predetermined by the "pattern field, the regulator stops building up tion of the predetermined time for which the dashpot 20 has been adjusted, thereby energizing the brake coil 21 to release the brake B to permit the car to move freely by the circuit when the up direction switch U was energized and closed its contact members U4, the high speed relay V was energized to close-its contact members VI. The closing of the contact members VI short circuits the portion of the resistor and thereby increases the energization of that field winding to increase the current supplied by the regulator to the generator field winding, thus causing the car to operate at its normal high speed.

If for any reason the loading on the car affects the hoisting motor sufiiciently to cause a drop in the voltage of the generator, the strength of the regulator difierential field will be less than that of the pattern field and the voltage difierent'ial will be set up in the regulator, which by the action of its self-exciting field, will quickly and smoothly bring the generator voltage to the value indicated by the controller or pattern field.

Furthermore, as stated before, the regulator series field winding RSF will cause the regulator R to give the generator field winding GF sufficient excitation to compensate for the RI drop in the hoisting motor H and, the net result will be a constant speed for the hoisting motor regardless of the load and regardless of the selected value of that speed, and anything which tends to disturb this relation will be automatically compensated for by the reaction of the field windings as previously described.

The car is now moving up the hatchway at its normal high speed.

It will be assumed now that thecar approaches a fioor at which the attendant desires to make a stop, and that he thereupon centers the car switch CS to cause the car to stop at the desired fioor.

Briefly, the centering of the switch CS energizes the decelerating relay E, which, when it arrives at thedecelerating plate UE, deenergizes the speed relay V to decelerate the car. The deenergized relay V energizes the stopping relay F which,.when it arrives at the stopping plate UF, deenergizes the up direction relay, which, in turn, deenergizes the pattern field REF to stop the hoisting motor and apply the brake B to land and hold the car at the floor.

This operation, in detail, is carried out as follows: The centering of the car switch opens its contact members 22 and CS1, but the up direction switch remains energized because of its self-holding contact members U5. However, the centering of the car switch closesits contact members CSI and 28, thereby energizing the decelerating inductor relay E to effect deceleration of the car from its normal high speed to its stopping speed by the circuit L-l-I, cs, csazs, E, vs, L l

The energized inductor relay E does not at once effect the opening of its contact members El and E2, but assoon as the car arrives at the up direction inductor plate UE, that plate operates the relay to open its contact members El, thereby deenergizing the high speed relay V, which in turn opens its contact members VIand thereby reinserts the resistor r3 in circuit with the pattern field RPF. The inclusion of theresistor r3 in this 1'3 in the circuit of the pattern field winding RPF field winding decreases its energization and thereby causes acorresponding decrease by the regulator R 01' the energization of the loop circuit it including the generator field winding G1". The decrease in the energization of the generator field winding causes the generator armature to supp y less current to the hoisting motor and thereby decreases the speed of the car.

It should be noted here that the eii'ect oi the decreased current fiowing in the loop circuit l1 causes the difi'erential field winding RD! 0! the regulator to be so changed in energization that it cooperates with the pattern field to cause the regulator to quickly and smoothly bring the generator'voltage down to the value indicated by the pattern field.

When the high speed relay V was deenergized, it closed its back contacts V2 and thereby completed a circuit for energizing the coil of the stopping inductor relay l", by the circuit L+|, cs, 081, a, r, vans, L-l

It will be assumed now that the car arrives within stopping distance of the fioor, at which the stop is to be made, and thus brings the inductor relay F opposite its stopping inductor plate U1". The plate causes the relay to open its contact membersFl and thereby deenergize the up direction switch U. The deenergization oi the up direction switch U opens its contact members Ul,

thus deenergizing the brake coil 21 to apply the brake B to hold the car, and at the same time, opens its contact members U2 and U3, thus deenergizing the pattern field RPF. The deenergization of the pattern field causes the regulator to stop supplying voltage to the generator field winding GF, which, in turn, causes the generator armature GA to stop supplying current to the hoisting motor, thereby stopping the hoisting motor. The stopping of the hoisting motor and the application of the brake stops the car at the' floor.

variable voltage systems have been eliminated. 4 The elimination oi these two fields from the generator further contributes to the reduction of cost of the whole system.

Another valuable feature of this control system is-that the adjustable resistor rl disposed in series with the regulator field winding RDI", provides a ready control over the rate .01 acceleration and retardation of the elevator car,' which depends on the amount of resistance in series with the difierential-field. When this resistance is low, the generator voltage builds up or down quickly, and when the resistance is high, the changes are much slower. This is a valuable advantage in elevator control systems involving inductor relays and inductor plates, because with it the inductor plates may be disposed at definite points from the fioor for any desired-stoppin speed and then theresistor may be adjusted to cause the car to decelerate at the correct speed from that plate to arrive at the proper landing speed adjacent to the fioor at which the stop is to be made. Heretofore, when the car began to tail to decelerate to the proper landing speed, it was necessary to physically adjust the plate either up or down the hatch- My improvement provides a big saving in that it permits the plate to be placed at approximately the correctposition and then the system' adjusted to the position of the plate, it being much more convenient to change the value of the resistor than to enter the hatchway and change the location of the plate.

Although I have illustrated and described only one specific embodiment of my invention, it is to be understood that changes therein and modifications thereoi may be made without departing from the spirit and scope oi the invention.

I claim as my invention:

1. In a variable voltage system of control, the combination of a motor having a field winding and an armature operable at a plurality oi speeds, a power generator having a field winding and an armature driven at approximately constant speed. said generator armature being connected in loop circuit with the motor armature, a regulating generator having an armature and a self-exciting field winding, a second loop (circuit including the self-exciting field winding and the armature of the regulating generator and the field winding of the power generator, a second field winding on the regulating generator connected to carry at least a portion of the current fiowing in said first named loop circuit, a third field winding on the regulating generator connected across the terminals o! the armature of the power generator, and a fourth field winding no the regulating generator connected to an external voltage supply for controlling the output oi electrical energy by v the regulating generator.

2. In a cascade connection of a pair 01' generators delivering energy to a motor, a loop circuit 35 erator and a field winding of the first named generator, said latter winding being so proportioned that oneempere of current flowing in it produces Just enough voltage at its associated armature to circulate one ampere through the loop circuit.

3. In a cascade connection of generators for controlling the speed of a motor wherein the armature of one generator excites a second generator field winding to produce voltage on the second generator to thereby circulate current in the armature of said motor, the combination of a field winding on said first named generator connected across the armature of said second named generator, and current regulating means for varying the strength of said field winding for a given armature voltage to thereby produce a plurality of rates 01 building up and dying down of the speed of said motor.

4. A variable voltage system oi'control comprising a power generator provided with an armature and a field winding and a motor connected in a loop circuit with said armature, a regulating generator for energizing a field winding oi the power generator, said regulating generator having an armature, a series field winding connected to carry at least a portion of the current fiowing in the loop circuit connecting the power generator and the motor, a difierential field winding connected across the terminals of the" power generator armature, a self-exciting field winding connected in loop circuit with the power generator field winding and the regulating generator armature, and a pattern field winding connected to an external supply of electrical energy for controlling the output of electrical energy by the regulating generator to the power generator.

5. A variable voltage system of control com- 2,221,610 prising a power generator provided with an armature and a field winding, a motor connected in a loop circuit with saidarmature, aregulating generator for energizing the field winding of the power generator, said regulating generator having an armature, a series; field winding connected to carry at least a portion of the current flowing in the loop circuit connecting the power gen erator and the motor, a differential field winding connected across the terminals oi! the power generator armature, a salt-exciting field winding connected in loop circuit with the power generator field winding and the regulating generator armature and a pattern field winding connected to an external'supply oi, electrical energy for controlling the output of electrical energy by the regulating generator to the power generator, and a controller for varying the amount of electrical energy delivered to the pattern field winding to secure a plurality of predetermined speeds of operation of the motor.

6. Ina variable voltage system of control, a motor connected to a load device, a power generator for energizing the motor, said'generator having a field winding and a regulating generator for supplying energy to the field winding of the power generator, said regulating generator having a series of field winding connected to carry at least a portion of the current flowing from the power generator to the motor-to cause the regulating generator to give the generator field winding sufiicient excitation to compensate for the RI drop in the hoisting motor,a pattern field winding connected to an external supply of electrical energy for causing the egulating generator to supply predetermined values of electrical energy to the power generator field winding to cause that generator'to deliver power to the motor, a difierential field winding connected across the terminals of the power generator armature for balancing the excitation of the pattern field winding, and a self-exciting field winding connected in loop circuit with the field windfor supplying energy to the field winding of the power generator, said regulating generator having a series field winding connected to carry at least a portion of, the current flowing from the 4 terminals of the power generator armature for balancing the excitation of the pattern field winding, a self-exciting field winding connected in loop circuit with the field winding of the power generator and the armature of the regulating generator, and a resistor connected in circuit with the difierential field winding for adjusting the value of the difierentialfield winding to regulate the rate of deceleration of 'the motor.

8. In a. variable voltage system of control. an

exciter for supplying electrical energy to a control circuit; a motor having an armature and a field winding, said field winding b61118 connected to said control circuit; a power. generator having a field winding and an armature, a loop circuit c'onnecting the armature oi the power generator to the armature of the motor; a regulating generator tor energizing the field winding of the power generator, said regulating generator havpredetermined amount of electrical energy, a

self-exciting field winding connected in loop circuit with the field winding of the power generator and the armature of the regulating generator for causing the regulating generator to deliver a predetermined amount of electrical energyto the power generator field winding, and a diflerential fieldwinding connected across the terminals of the power generator armature for causing the regulating generator voltage to build up to the value indicated by the pattern field winding; and a driving motor for operating the exciter, 'the motor armature, the generator 'arma ture, and the regulating generator armature at constant speed.

9. A variable voltage control system for an elevator comprising a hoisting motor for operating an elevator car, said motor having an armature and a field winding; an electromagnetic brake forcontrolling the hoisting motor; a power generator having a field winding and an armature; a loop circuit connecting the motor armature and the power generator armature through which energy may be supplied from said generator to said motor; a regulating generator for energizing the field winding of the power generator, said regulating generator having an armature and a self-exciting field winding connected in loop circuit with the power generator field winding, a series field winding connected between the armature ofthe generator and the armature of the motor, a differential field winding connected acrossthe terminals of the power generator armature, and a pattern field winding connected to an external supply of electrical energy, said pattern field winding and said differential field winding being designed to produce the same and opposite voltage in the regulator for a given excitation oi the pattern field winding; switch means for connecting the pattern field winding to said external supply of electrical energy, and means responsive to operation of said switching tromagnetic brake upon the expiration of a. predetermined time after the pattern field'is energized. i

10. A variable voltage system of control com- .prising a motor; a' power generator having a field winding and an armature for energizing the motor; a regulating generator for energizing the field winding of the power generator, said regulating generator having an armatureanda self-exciting field winding connected in loop circuitgvith the field winding of the power generator whereby electrical energy is supplied to the power generator by the regulating generator, a series field winding connected in series with the power generator armature and the armature oi' the motor for causing the regulator to control the supply of energy to the motor, a platform field winding for causing the regulating Igenerator to deliver a predetermined amount of elec- -mechanism for effecting the release of the electricalenergytothefieldwindingoithepower generator and a difierential field winding connected across the terminals of the power generator armature tor contolling the efiect oi the pattern field winding on the regulating generator in accordance with a given excitation oi! the pattern field; switching means for connecting the pattern field to an external source of electrical energy, a resistor disposed in circuit with said pattern field. and a speed relay responsive to operation of the switching mechanisin for controlling the amount of resistance in circuit with the pattern field to determine the speed oi .the hoisting motor.

11. In a variable voltage system of control, a

motor, a power generator having a field winding namnoaam'nn. u 

